摘要
As one of the essential amino acids, methionine (Met) plays an important role in biological events such as methylation and antioxidant properties besides its function in protein synthesis. Different Met sources have been used in animal production, but their effects on Met metabolic pathways are not well understood. In the present study, we investigated the effects of different Met sources (L-Met, DL-Met, DL-2-hydroxy-4-(methylthio)butanoic acid (DL-HMTBA), and DL-methionyl-DL-methionine (DL-MM)) on the metabolism of Met in small intestinal porcine epithelial cell line (IPEC-J2) and the contents of extracellular Met sources. The results showed that concentrations of intracellular Met, S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), and the ratio of SAM to SAH in the DL-HMTBA group were significantly lower than that in other Met source groups, while the content of 5-methyltetrahydrofolate (5-MTHF) was significantly higher. Moreover, the mRNA levels of MAT2A, AHcy, CBS, MTHFR, and MTR in the DL-HMTBA group were significantly higher than those in other Met source groups. Further study showed that the total content of extracellular Met sources was highest in the DL-HMTBA group, followed by DL-MM group, followed by L-Met and DL-Met groups. These results demonstrated that DL-HMTBA mainly affects the transmethylation and remethylation of Met and it can promote the trans-sulfur metabolism of Met when compared with other Met sources. In addition, most DL-HMTBA and a small amount of DL-MM can escape the intestinal first-pass metabolism and then provide more extracellular Met sources than L-Met and DL-Met. Therefore, this study can provide a theoretical basis for the selection of Met sources in livestock.
摘要译文
蛋氨酸（Met）是人体必需的氨基酸之一，除了在蛋白质合成中起着重要的作用外，在甲基化和抗氧化等生物学事件中也起着重要的作用。不同的Met来源已用于动物生产，但对Met代谢途径的影响尚不十分清楚。在本研究中，我们研究了不同Met来源（L-Met，DL-Met，DL-2-羟基-4-（甲硫基）丁酸（DL-HMTBA）和DL-甲硫基-DL-蛋氨酸（ DL-MM））对小肠猪上皮细胞系（IPEC-J2）中Met的代谢及细胞外Met来源的含量。结果表明，DL-HMTBA组细胞内Met，S-腺苷甲硫氨酸（SAM），S-腺苷同型半胱氨酸（SAH）的浓度以及SAM与SAH的比例均明显低于其他Met源组，而5-甲基四氢叶酸（5-MTHF）的含量明显更高。此外，DL-HMTBA组中MAT2A，AHcy，CBS，MTHFR和MTR的mRNA水平显着高于其他Met来源组。进一步的研究表明，DL-HMTBA组中细胞外Met来源的总含量最高，其次是DL-MM组，其次是L-Met和DL-Met组。这些结果表明，DL-HMTBA与其他Met来源相比，主要影响Met的甲基化和再甲基化，并且可以促进Met的反硫代谢。此外，与L-Met和DL-Met相比，大多数DL-HMTBA和少量DL-MM可以先通过肠道代谢，然后通过代谢，然后提供更多的细胞外Met来源。因此，本研究可以为家畜中Met来源的选择提供理论依据。
Fangrui Zuo; Qiongyao Gu; Shengqing Li; Hongkui Wei; Jian Peng. Effects of Different Methionine Sources on Methionine Metabolism in the IPEC-J2 Cells[J]. BioMed Research International, 2019,2019